diff --git a/bin/init/common.sh b/bin/init/common.sh
index cc7f171..4cac6ad 100644
--- a/bin/init/common.sh
+++ b/bin/init/common.sh
@@ -128,6 +128,14 @@ install_or_upgrade_homebrew_linux() {
   activate_brew_shellenv
 }
 
+# Refresh Homebrew itself before touching any formula. CI runners ship a
+# preinstalled Homebrew with auto-update disabled, and a Homebrew older than the
+# formula JSON API's schema aborts mid-pour with "unknown install step: run".
+update_homebrew() {
+  brew update
+  brew upgrade
+}
+
 install_or_upgrade_brew_formula() {
   local formula
   formula="$1"
diff --git a/bin/init/macos.sh b/bin/init/macos.sh
index 40dad53..0deca5d 100644
--- a/bin/init/macos.sh
+++ b/bin/init/macos.sh
@@ -78,7 +78,7 @@ fi
 export PATH="/usr/local/bin:$PATH"
 export PATH="/opt/homebrew/sbin:$PATH"
 export PATH="/opt/homebrew/bin:$PATH"
-brew upgrade
+update_homebrew
 brew doctor || true
 log_step "Homebrew installed"
 
@@ -196,6 +196,7 @@ install_go_tool "github.com/mikefarah/yq/v4@latest"
 install_go_tool "github.com/x-motemen/ghq@latest"
 install_go_tool "github.com/cloudspannerecosystem/spanner-cli@latest"
 install_go_tool "github.com/aquasecurity/tfsec/cmd/tfsec@latest"
+install_go_tool "github.com/terraform-linters/tflint@latest"
 install_go_tool "mvdan.cc/gofumpt@latest"
 install_go_tool "tailscale.com/cmd/tailscale@main"
 install_go_tool "tailscale.com/cmd/tailscaled@main"
diff --git a/bin/init/ubuntu.sh b/bin/init/ubuntu.sh
index 55b0056..40c165b 100644
--- a/bin/init/ubuntu.sh
+++ b/bin/init/ubuntu.sh
@@ -75,7 +75,7 @@ install_or_upgrade_git_repo "https://github.com/ebkn/dotfiles" "$DOTFILES_DIR"
 
 log_step "Installing Homebrew"
 install_or_upgrade_homebrew_linux
-brew upgrade
+update_homebrew
 brew doctor || true
 
 log_step "Installing Google Cloud CLI"
@@ -113,6 +113,7 @@ install_go_tool "github.com/mikefarah/yq/v4@latest"
 install_go_tool "github.com/x-motemen/ghq@latest"
 install_go_tool "github.com/cloudspannerecosystem/spanner-cli@latest"
 install_go_tool "github.com/aquasecurity/tfsec/cmd/tfsec@latest"
+install_go_tool "github.com/terraform-linters/tflint@latest"
 install_go_tool "mvdan.cc/gofumpt@latest"
 install_go_tool "tailscale.com/cmd/tailscale@main"
 install_go_tool "tailscale.com/cmd/tailscaled@main"
diff --git a/bin/init/wsl.sh b/bin/init/wsl.sh
index a763e3d..c5f14fb 100644
--- a/bin/init/wsl.sh
+++ b/bin/init/wsl.sh
@@ -131,7 +131,7 @@ install_or_upgrade_git_repo "https://github.com/ebkn/dotfiles" "$DOTFILES_DIR"
 
 log_step "Installing Homebrew"
 install_or_upgrade_homebrew_linux
-brew upgrade
+update_homebrew
 brew doctor || true
 
 log_step "Installing Google Cloud CLI"
@@ -192,6 +192,7 @@ install_go_tool "github.com/mikefarah/yq/v4@latest"
 install_go_tool "github.com/x-motemen/ghq@latest"
 install_go_tool "github.com/cloudspannerecosystem/spanner-cli@latest"
 install_go_tool "github.com/aquasecurity/tfsec/cmd/tfsec@latest"
+install_go_tool "github.com/terraform-linters/tflint@latest"
 install_go_tool "mvdan.cc/gofumpt@latest"
 
 link_with_backup "${DOTFILES_DIR}/.vimrc" "${HOME}/.vimrc"
diff --git a/brewfiles/Brewfile-lang b/brewfiles/Brewfile-lang
index 5c6b950..584fd97 100644
--- a/brewfiles/Brewfile-lang
+++ b/brewfiles/Brewfile-lang
@@ -15,8 +15,9 @@ brew 'hadolint'
 # ShellScript
 brew 'shellcheck'
 
-# Terraform
-brew 'tflint'
+# Terraform: tflint relicensed to BUSL and was dropped from homebrew-core
+# (2026-05-13), so it is installed via install_go_tool alongside terraform-ls
+# and tfsec in the platform init scripts.
 
 # Java
 brew 'java'
diff --git a/zsh/alias.zsh b/zsh/alias.zsh
index bbfba11..4c87d23 100644
--- a/zsh/alias.zsh
+++ b/zsh/alias.zsh
@@ -529,6 +529,7 @@ update-all() {
   go install github.com/x-motemen/ghq@latest
   go install github.com/cloudspannerecosystem/spanner-cli@latest
   go install github.com/aquasecurity/tfsec/cmd/tfsec@latest
+  go install github.com/terraform-linters/tflint@latest
   go install mvdan.cc/gofumpt@latest
   go install tailscale.com/cmd/tailscale{,d}@main
   # --ignore-scripts=false overrides ~/.npmrc's global ignore-scripts=true: this